Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The real, complete, and sufficient knowledge of the current water situation in Mexico is necessary to generate policies that lead to concrete actions to address the water problem in the country. Determine the real value of water contributes to create direct, focused, and objective solutions, for which the value of water for irrigation was estimated through two methodologies, cost accounting and mathematical programming, to calculate the real value of water in the study area. The cost accounting considers the total of the costs incurred to obtain the water for irrigation and calculates its value as the sum of the costs. Mathematical programming considers water as a productive factor and establishes the value of water as the shadow price of the factor based on the technical coefficients of production. The total cost of water, which is from this perspective the real value of water, estimated with the first methodology was $ 1.03 m3. The mathematical programming showed a value of $ 0.95 m3 for the water shadow price.

Hurricane Stan (October 3 to 6, 2005) affected the Vicente Guerrero River basin, Siltepec, Chiapas, Mexico, socially, economically, hydrologically, and hydraulically. On October 5, 2005, the maximum precipitation of 552 mm/day fell. Through hydrological modeling, with the HEC-HMS model, a peak flow of 460.1 m3/s at the outlet of the basin and the hydrographs at the exit in each sub-basin were obtained. These data were used in hydraulic modeling with the IBER model, which reported maximum levels of 5.75 m and maximum speeds of 11.38 m/s in the channel. Flood bandwidths of 100 m were generated on both banks. The results were validated with the information of a Bing Maps satellite image of December 2005, observed at the passage of the hurricane, comparing the coordinates, X, Y, and Z, of the simulated event against the observed event, achieving r2 = 0.99 for each margin. With this information, a "hazard map" was generated, by IBER's ACA Standard, which showed that more than 80 % of the area of the flood envelope is in very high danger.

To improve the predictions of a deterministic hydrological model, it is necessary to calibrate and validate the model so that it can be used to predict the system’s behavior reliably for different conditions. This article presents the implementation of a methodology for calibration/validation deterministic hydrological models. Three blocks were considered: 1) creation and generation of precipitation intensities and random parameters to be used to obtain the simulated flows, which were stored in a database administrator; 2) the parameters obtained in block 1, are grouped to obtain the interval frequencies; 3) combination of the interval frequencies of the most influential parameters, to obtain the best combination. The methodology developed was applied to three sub-basins of the Meléndez River, in Cali, Colombia. We used more than 40 rain events in each case, and we applied the Storm Water Management Model (SWMM) to simulate the flow. The Nash-Sutcliffe determination coefficients were used to evaluate the calibration/validation process. The values obtained were more significant 0.70 for three events in the three sub-basins. It was evidenced that it is possible to find a set of feasible parameters that adjust to the different events evaluated.

While the need to use clean, renewable energies in electricity generation is universally understood, Mexico is lagging behind other countries regarding the contribution these sources have to the production of energy nationally. The first hurdle to overcome is providing accurate information for decision-makers and potential investors. In the case of renewable marine energy, this means generating data on the possible installed electrical capacities of the various sources at sites across the country. From this, it is possible to estimate the economic viability of implementing renewable energy projects at specific locations. This work, therefore, aims to characterize the available power from diverse energy sources around the coasts of Mexico and to make recommendations of sites where the energy potential warrants further analysis. A literature review of the power available from marine currents, waves, and thermal and saline gradient sources was performed for the Mexican Caribbean. Several sites were found to be geographically viable; there is sufficient potential energy available to meet at least part of the energy demands of the Yucatan Peninsula and Cozumel Island. Key sites are to the south of Cozumel Island and in the Cozumel Channel for energy harvested from ocean currents. In the northern part of Quintana Roo, sites offer great potential for wave energy, while the central part of the state could be suitable for energy generation from thermal gradients. In Chetumal Bay, there is potential for saline gradient electricity. Wave energy potential was evaluated for the entire Mexican coast, and seven locations are recommended for further investigation. A conservative gross estimation has shown that wave energy could contribute up to 0.2 % of the national demand in the short or mid-term, with a relatively small investment and a low environmental impact.

Background. Plant catalogues are basic to propose and manage natural protected areas. Through those censuses plans and conservation strategies are developed, plus comparisons can be made over time. Updated floristic listings are urgent in tropical forests due to the threats to their biodiversity. Objective. Present a structured listing by family, genus and species, which quantifies the hierarchical relations of genera-species and family-genera while arranging life-forms and including species with endangered status recorded in national (NOM-059 SEMARNAT 2010) and international (Red list, UICN) legislation of woody and semi-woody plants from dry and semi-humid forest from the Área de Protección de Flora y Fauna Meseta de Cacaxtla, Sinaloa, México (APFFMC). Methodology. Published studies about the site were reviewed, selecting the indigenous species with secondary growth, excluding the invasive, naturalized, cultivated, ornamental ones, collating different online sites, specialized bibliography and consulting specialists. Regarding the nomenclature different sources and databases were employed. Through field trips, the presence of taxa was corroborated and new registers were included. The listing was sorted alphabetically. Results. 60 families, 223 genera and 389 species were recorded. Fabaceae was the family with the highest taxa richness, with 44 genera and 75 species, followed by Malvaceae (19/31), Euphorbiaceae (12/34), Asteraceae (10/17), Cactaceae (9/21) and Apocynaceae (8/10). A low number of 13 genera and 12 families gathered five or more species and genera respectively. On the other hand, a high quantity of 210 genera and 48 families presented four or less taxa. The most diverse genera were Croton (12 species), Bursera (8), Solanum (7), Ficus and Randia (6); Opuntia, Merremia, Euphorbia, Lonchocarpus, Mimosa, Senna, Jatropha and Sideroxylon (5). The tree category grouped 146 species, followed by shrub (114), sub-shrub (54), vine (51), succulent and semi-succulent (21) and parasitic (3). According to the NOM 059 SEMARNAT-2010 endangered species list, five species were included in the Amenazadas (A) category and two Sujetas a protección especial (Pr). The red list (UICN) comprehended 173 species for the Natural Protected Area (ANP). In the Least concern category (LC) 155 taxa were counted, Near threatened (NT) with four, Vulnerable (V) seven and Endangered (EN) again seven. Implications. A renewed listing of alien, native, woody and semi-woody species from dry and semi-humid forests of the APFFMC, is crucial for its contribution to a proper management and decision taking in the ANP. 94 taxa names were updated. At family level, the inclusion of Sterculiaceae into Malvaceae was the most significant change. Conclusions. The taxonomic richness concentrated inside the APFFMC, whose surface is inferior to 1% of the state, oscillates between 10.41 and 13.93% of the species; 19.95 and 22.80 % of the genera and 29.70 and 30% of the families reported in the state of Sinaloa, Mexico.

Background. Small ruminants from subtropical regions are sensitive to respond physiologically to natural photoperiodic changes. In some subtropical goat production systems as located in semi-arid areas of México, the main objective is to obtain in the shortest possible time, males with a suitable weight and body development for sale. Objective. The present study determines if the exposure to artificial long day photoperiod could promote a growth rate, body development and an increased glycemia in male goat kids compared with those under natural short days. Methodology. Starting on late September, 21 creole male goat kids (13 ± 0.1 week aged; mean ± SEM) were assigned to one of the two experimental groups. In the natural short days group, males remain under natural short days from autumn-winter (GDC, n = 10). In the artificial long days group, males were exposed to artificial photoperiod consisting in 16 h light and 8 h darkness (GDL, n = 11). The study lasted until the animals had 35 weeks of age. All animals were fed according their nutritional requirements. Results. During the study, the body weight of the GDL animals was higher than that of the GDCN males (P < 0.05). Due to this, the daily weight gain (GDP) obtained at 23 weeks of age was higher in the GDL males (165 g/day) than that registered in the GDC males (143 g/day; P <0.05). In some periods, the males of the GDL had higher body mass index (IMC) than the males of the GDC (P < 0.05). Thoracic perimeter at week 32 was greater in the GDL males than in the GDC males (P <0.05). The height at the withers did not reach significant differences in the comparisons between groups in the different weeks measured (P > 0.05). However, the total height at the withers gained during the study was significantly higher in the GDL males than in the GDC males (P < 0.01). Under fasting conditions, GDL males had higher levels (P < 0.05) of blood glucose in some periods than GDC males. Implications. The present study demonstrate that artificial long days stimulates growth in goats as occurs in other ruminants. Conclusion. Exposure of the male goat kids from subtropical regions to artificial long days, promotes a higher growth rate, better body development and increased glycemia compared to kids maintained under natural short-day photoperiods.

Background. Worldwide, gastrointestinal nematodes (GIN) cause losses in livestock production, because in some animals they can cause weight loss or death. Combating these GIN has been based on the use of anthelmintics. However, the misuse of these treatments has caused anthelmintic resistance. Therefore, there is currently a search for new biological alternatives for the control of gastrointestinal nematodes. One of these alternatives is the use of fungal extracts for nematode control. Objectives. To utilize the in vitro larval exsheathment inhibition test to evaluate organic extracts of edible fungi Pleurotus eryngii, P. djamor and Lentinula edodes, against Haemonchus contortus (L3). Methodology. Extracts were prepared from the basidiomes of the fungal species mentioned. In the case of P. eryngii and P. djamor, they were placed in a hydroalcoholic mixture (methanol/water 70:30). On the other hand, L. edodes basidiomes were macerated with distilled water for 24 hours. The extracts were filtered with a cotton/gauze system and through Whatman paper (#4) and were concentrated using a rotary evaporator until the liquid residue was removed and kept at -4 °C until use. To determine the percentage of larval exsheathment inhibition, larvae were exposed to different concentrations (156.25, 312.5, 625, 1250, and 2500 µg/mL) with their respective negative controls (PBS) for 60 minutes. The effective concentration 50% (EC50) was calculated by means of probit analysis. Results. The extracts with the best activity were P. djamor and L. edodes with an effective concentration (EC50) of 533.3 and 558.5 µg/mL, respectively. Implications. This in vitro evaluation provides results that suggest the need for further in vitro studies with more fungi species and other types of extraction procedures. Conclusion. The present study demonstrated that the use of extracts of P. eryngii, P. djamor and L. edodes was shown to have in vitro anthelmintic activity against the larval exsheathment of H. contortus.

Background: The cacao agroforestry system (Cacao-AFS) is a small-scale design system with a great diversity and multiple functions; at the same time that is very vulnerable to the climatic variability. Through resilience is possible to see, how does a system respond and/or reorganize in the face of a perturbation like climate change. This work makes a review of Cacao-AFS and analyzes its potential resilience to climate change. Methodology: A review of the state of the art about the cacao system and its resilience had been organized from an analysis of 249 works consulted from bibliographic bases. The information was codified in six factors (scientific and contemporaneous knowledge, agrobiodiversity, socioecological autoregulation, capital, and social self-organization) and climate change implications, and finally evaluated through a matrix. Results: Through the review of the literature, it was found that there is a great adaptive capacity because scientific innovation and contemporaneous knowledge it generates different actions to solve some problems of the system. Also, it was found that there is a great agrobiodiversity in the system that allows the socioecological reproduction of the system (autoregulation). On the other hand, the system is low rentable and the young people don`t want to incorporate to the activity (low capital) and the social actors don´t use to cooperate (low self-organization). Implications: It was found that there are some aspects that favor the resilience of cacao system and others that need to be improved. To improve the resilience of the Cacao-AFS to climate change it is necessary to create spaces for the self-organization of the different actors and the knowledge dialogue, and to make a transition to more just and agroecological schemes. There are still some parts of the systems and their resilience that had not been totally investigated, like the local responses of the communities to climate change, the immaterial life of the cacao peasants, their inter-familiar and inter-community links, the environmental history of the cacao system, the functional and respond biodiversity and holistic economic diagnostics. Conclusions: The cacao system had some elements that indicate some degree of resilience to the climate change. The cacao system is resilient to climate change in some factors and not resilient in others. Their investigation is a fertile field to make multi and interdisciplinary studies.

Background. Some secondary metabolites found in plants have been used to control pests and pathogens. The plant Embelia schimperi contains complex compounds that can be used to biosynthesize agrochemicals for the control of plant-parasitic nematodes. Objective. This work analysed the phytochemical profile of the E. schimperi plant and assessed the biological potential of its crude extracts. Methodology. The phytochemicals were extracted in three solvents: ethanol, dichloromethane, and hexane, utilising maceration and ultrasonication procedures. Results. These solvents performed well in extracting flavonoids, phenolics, terpenoids, tannins, and saponins, according to the findings. Implication. The root-knot nematode Meloidogyne incognita can be inhibited from hatching, and the lesion nematode Pratylenchus zeae can be killed as a result of these chemicals' bioassay activities. Conclusion. Plant-parasitic nematode may be controlled with crude extracts from this plant, which can be processed into a botanical insecticide.

In this study, operating policies of the Z curves type were obtained, using two optimization methods: the Generalized Reduced Gradient (GRG) Nonlinear and a simple Genetic Algorithm (GA), and they were applied to a reservoir located in the Cuitzeo lake basin, which plays an important role in supplying water to a part of the population of the city of Morelia and in the irrigation of several modules of the Irrigation District (DR) 020, known as Morelia-Queréndaro. With each policy obtained, the operation of the system was simulated, using the historical record of inflow volumes into the system, to compare with the reported by the National Water Commission (Conagua) and those that maintained the balance between compliance with demands and less presence of spills or deficits. Finally, to review the behavior of the system in the long term when using the selected policies, a series of synthetic monthly inflow volumes with 100 years of record were simulated, generated with the Svanidze method. The comparison of the deficit and spillage results at the monthly and annual level of the simulations carried out with the historical Z curve, GA and GRG, indicated that the GA had an acceptable behavior both in the historical period and in the long term, since, although the volumes spilled increased, the magnitude in which they did so is less than the magnitude in which the deficit was reduced and as the Cointzio dam has been used to supply water to the Vista Bella water treatment plant and for irrigation of 4 of the 5 modules of the irrigation district 020, the operating rule that best controlled the deficit event was chosen.